Dental microwear and dental ecology

Age-related variability in buccal dental-microwear in Middle and Upper Pleistocene human populations

2011-12-19T12:45:00.000+01:00

Buccal dental surfaces with dietary microstriations

A paper on dental microwear in Pleistocene humans, including Homo heidelbergensis, Homo neanderthalensis and Homo sapiens has been published at Anthropological Review.

The conclusions of this work are that buccal microwear striation pattern is a characteristic trait of a population reflecting long-term dietary shifts. Results from this study indicate that infants have a consistently high-density microwear pattern, similar to that of the adult individuals in all three populations studied: Homo heidelbergensis, Homo neanderthalensis and Homo sapiens (anatomically modern humans). The shift towards adult dietary behavior appears to have taken place at around 13 years of age. From this age onwards, age did not seem to affect the microwear pattern observed in the archaic humans, whereas in modern humans a cumulative pattern with age was observed. Therefore, the individual age-at death should be taken into account when analyzing buccal microwear, especially in children. When analyzing the same ages, infant feeding behavior appears to have been different among the species, especially in AMH, whose infants seem to have less abrasive dietary habits compared to their predecessors.
However, these results need to be considered along with changes in geography, chronology and climate, all of which might have played an important role in food availability and consumption in Paleolithic hominins.

Here you have the abstract and a link to the original paper.

Age-related variability in buccal dental-microwear in Middle and Upper Pleistocene human populations

Beatriz Pinilla Pérez, Alejandro Romero & Alejandro Pérez-Pérez

ABSTRACT
Infants are thought to present a different buccal microwear pattern than adult and these, therefore, are generally analyzed separately. However, El-Zaatari & Hublin [2009] showed that occlusal texture in Neanderthal and modern human juvenile populations did not differ from their elders. The microwear patterns of a sample of 193 teeth, corresponding to 61 individuals of Homo heidelbergensis, H. neanderthalensis and anatomically modern humans (AMH), were analyzed revealing that AMH infants up to 14 years old differ from older individuals in having fewer scratch densities, whereas the Neanderthals have a much more variable microwear pattern. Age-at-death and dental age since emergence showed similar though somewhat diverging results, especially in the infant and sub-adult samples. Differences observed between the Neanderthals and modern humans could be reflecting differential wearing patterns or distinct enamel structure and resistance to hard food items consumption. Interpopulation differences in striation densities were not apparent in either sub-adult or adult individuals, only adult Neanderthals (26-45 yrs. old) showed fewer striations than the younger age groups. The AMH sample revealed a gradual cumulative pattern of striation density with age, suggestive of a non-abrupt change in diet.

KEY WORDS: microwear, age, teeth, Neanderthals, humans

Genes, ciencia y dieta

2011-10-01T12:16:00.000+02:00

A new book on human evolution and diet has been published by Instituto Tomás Pascual para la nutrición y la salud and Centro Nacional de Investigación sobre la Evolución Humana, edited by A. Mateos Cachorro and A. Perote Alejandre. One of the chapters is about dental microwear and feeding ecology in early hominins, and shows part of the research done in our lab.

Here you have the citation:
Estebaranz F, Galbany J, Martínez LM & Pérez-Pérez A (2011) Las dietas de los hominini plio-pleistocénicos de África del este y del sur: del bosque cerrado a las sabanas abiertas. In: A Mateo Cachorro, A Perote Alejandre (Eds.), Genes, ciencia y dieta. Lecciones sobre evolución humana. Pp: 41-66. Instituto Tomás Pascual para la nutrición y la salud; y Centro Nacional de Investigación sobre la Evolución Humana. Madrid.

You can download the pdf of the whole book for free!

Myosin expression and primate locomotion

2011-09-17T19:15:00.000+02:00

We post again about anatomy and locomotion in primates because recently has been published a paper at the International Journal of Primatology coauthored by Gaëlle Bello and Josep M. Potau, both researchers in our group.

Josep Maria Potau, Rosa Artells, Gaëlle Bello, Carmen Muñoz, Mariano Monzó, Juan Francisco Pastor, Félix de Paz, Mercedes Barbosa, Rui Diogo and Bernard Wood (2011) Expression of myosin heavy chain isoforms in the supraspinatus muscle of different primate species: Implications for the study of the adaptation of primate shoulder muscles to different locomotor modes. International Journal of Primatology 32(4): 931-944.

Abstract
The supraspinatus muscle is a key component of the soft tissues of the shoulder. In pronograde primates, its main function, in combination with the other rotator cuff muscles (subscapularis, infraspinatus, and teres minor), is to stabilize the glenohumeral joint, whereas in orthograde primates it functions together with the deltoid, to elevate the upper extremity in the scapular plane. To determine whether these functional differences are also reflected in the molecular biochemistry of the supraspinatus muscles involved in these different locomotor modes, we used real-time polymerase chain reaction (RT-PCR) to analyze the expression of the myosin heavy chain (MHC) isoforms in supraspinatus muscles from modern humans and 12 species of pronograde and orthograde primates. The MHC expression pattern in the supraspinatus muscle of pronograde primates was consistent with its function as a tonic and postural muscle, whereas the MHC expression pattern observed in the supraspinatus muscle of nonhuman orthograde primates was that of a muscle that emphasizes speed, strength, and less resistance to fatigue. These findings are consistent with the role of the supraspinatus in the posture and locomotor modes of these groups of nonhuman primates. The humans included in the study had an expression pattern similar to that of the nonhuman orthograde primates. In conclusion, molecular analysis of skeletal muscles via RT-PCR can contribute to a better understanding of the morphological and functional characteristics of the primate musculoskeletal system.

Keywords: Myosin heavy chain, primate locomotion, Real-time polymerase chain reaction, supraspinatus

Amboseli baboons tooth wear in Portugal and Andorra

2011-08-24T19:45:00.001+02:00

Next September we will present our results about Amboseli baboons tooth wear at the IV Congress of the European Federation for Primatology / III Iberian Primatological Conference “Diversity within Primatology” in Almada, Portugal; and also at the XI Congreso Nacional de Paleopatología, in Andorra.

Here you have the abstracts

Tooth wear causes in Amboseli baboons
Jordi Galbany, Laia Dotras, Jeanne Altmann, Alejandro Pérez-Pérez & Susan C Alberts

The study of teeth in wild primate populations, such as baboons (Papio cynocephalus) from Amboseli (Kenya), allow obtaining unique information about the tooth wear dynamic formation and determine which processes are involved in other dental ecology aspects. The present dental study started in 2006, and is included in the Amboseli Baboon Research Project (since 1971). We darted baboons in order to obtain biological data, including tooth moulds. Until now, we have already taken over 150 moulds from known-aged individuals, both sexes, belonging to five different social groups in the same population. The analyses of teeth show a clear macroscopic transformation associated with aging. We calculated the % of dentine exposure and the dental crown relief as indicators of occlusal wear. These two variables present a high correlation with age for both sexes and all molars. Moreover, tooth wear is also significantly correlated with the individual food choice, in particular the consumption of abrasive food (grass corms). In addition, premolars (P4) and first molars (M1) present a significant interproximal wear correlated with age. In conclusion, morphological changes in teeth are strongly associated with aging processes, but also ecological factors. Future studies of biological variables, such as reproductive success or the individual survival, will determine if dental aging imply a loss of dental function, related to fitness. Funding: NSF, Princeton University Center for Health and Wellbeing, National Institutes of Health, Spanish projects. Supported by the ‘Dept. Educació i Universitats de la Generalitat de Catalunya and ‘Beca Floquet de Neu, Barcelona de Serveis Municipals SA. Keywords: Papio cynocephalus, tooth wear, aging, foraging.

Causas del desgaste dental en los babuinos de Amboseli: un modelo de primate de sabana in vivo
Jordi Galbany, Laia Dotras, Jeanne Altmann, Alejandro Pérez-Pérez & Susan C Alberts

La cuantificación del desgaste dental tradicionalmente se ha utilizado para asignar la edad de muerte en análisis antropológicos. Sin embargo, se han descrito numerosas limitaciones en este método, especialmente cuando se utiliza como indicador único, en parte porque el proceso de atrición sigue siendo poco conocido y sus causas son múltiples. Sin embargo, esta relación también se ha descrito en numerosas especies de mamíferos, incluyendo primates. El presente trabajo, realizado en babuinos (Papio cynocephalus) en libertad, pretende añadir nuevos datos sobre la relación entre el desgaste dental y sus causas. Este estudio, incluido en el “Amboseli Baboon Research Project”, empezó en 2006 mediante la captura de babuinos de Amboseli (Kenya) y la obtención de moldes dentales (hasta la fecha más de 150 individuos de ambos sexos y edad conocida). A partir de los moldes se realizaron réplicas de la dentición izquierda superior e inferior, y se cuantificó el porcentaje de exposición de dentina de cada molar a partir de imágenes digitales. Las variables consideradas para explicar el desgaste dental en esta población fueron: edad, porcentaje de consumo de alimentos abrasivos (rizomas subterráneos), esfuerzo materno y rango social. Los resultados obtenidos muestran correlaciones muy significativas entre la edad y el desgaste dental, en todos los molares y ambos sexos. Entre el resto de variables, únicamente el porcentaje de consumo de alimentos abrasivos correlacionó significativamente con el desgaste dental. Finalmente, se detectó un fuerte desgaste dental interproximal, especialmente en P4 y M1, también correlacionado significativamente con la edad.

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Más información:

Galbany J, Dotras L, Alberts SC & Pérez-Pérez A (2010) Tooth size variation related to age in Amboseli baboons. Folia Primatologica 81(6): 348-359.

Galbany J, Altmann J, Pérez-Pérez A, Alberts SC (2011) Age and individual foraging behavior predict tooth wear in Amboseli baboons. American Journal of Physical Anthropology 144(1): 51-59.

New dissertation on dental microwear and dental morphology in East African Australopithecus

2011-07-12T20:01:00.000+02:00

Following July 20th, Ferran Estebaranz will present his dissertation titled “Modelos de evolución morfológica de la dentición, fluctuaciones climáticas, patrones alimentarios y ecología de los Hominini PlioPleistocénicos de África del Este Australopithecus anamensis y Australopithecus afarensis”, directed by Alejandro Pérez-Pérez and Daniel Turbón. The presentation will be at “Aula 18”, 12 pm, Fac Biologia, Universitat de Barcelona.

This work has analyzed the buccal dental microwear pattern and dental morphology in Australopithecus anamensis and Australopithecus afarensis from different east African sites to trace dietary specializations. The results clearly show differences between the species and support that dietary specialization might have been a means to avoid ecological competition between hominids.

Some of the results presented here have been already published. Feel free to ask for any of these papers.

Estebaranz F, Martínez LM, Galbany J, Turbón D & Pérez-Pérez A (2009) Testing hypotheses of dietary reconstruction from buccal dental microwear in Australopithecus afarensis. Journal of Human Evolution 57: 739-750.

Galbany J, Estebaranz F, Martínez LM & Pérez-Pérez A (2009) Buccal dental microwear variability in extant African Hominoidea primates: taxonomy versus ecology. Primates 50(3): 221-230.

Estebaranz F, Galbany J, Martínez LM & Pérez-Pérez A. (2007) 3-D interferometric microscopy applied to the study of buccal enamel microwear. In: SE Bailey & JJ Hublin (Eds.) Dental perspectives on human evolution, 389-401. Springer.

Gómez-Robles A, Martinón-Torres M, Bermúdez de Castro JM, Margvelashvili A, Bastir M, Arsuaga JL, Pérez-Pérez A, Estebaranz F & Martínez LM (2007) A geometric morphometric analysis of hominin upper first molar shape. Journal of Human Evolution 53(3): 272-285.

Estebaranz F, Galbany J, Martínez LM, Pinilla B & Pérez-Pérez A (2006) Nota metodológica: Alteración del patrón de microestriación dentaria por el efecto wrinkle. Revista Española de Antropología Física 26:107-113.

Galbany J, Estebaranz F, Martínez LM, Romero A, De Juan J, Turbón D & Pérez-Pérez A (2006) Comparative analysis of dental enamel polyvinylsiloxane impression and polyurethane casting methods for SEM research. Microscopy Research and Technique 69(4): 246-252.

Estebaranz F, Martínez LM, Hiraldo O, Espurz V, Bonnin A, Farrés M, Pérez-Pérez A (2004) Tooth crown size and dentine exposure in Australopithecus and early Homo: testing hypotheses of dietary related selective pressures. Anthropologie 42(1): 59-63.

Fourier analysis error rates in Hominoidea molars

2011-07-01T08:00:00.001+02:00

A new paper on Hominoidea tooth morphology and Fourier analyses has been accepted recently at the “Revista Española de Antropología Física”

Gamarra B, Romero A, Pérez-Pérez A & Galbany J (2011, accepted) Análisis del error de medición y variabilidad interespecífica morfométrica de Fourier en M₂ de primates Hominoidea / Error rates and interespecific variability in mophometric Fourier analysis in M₂ Hominoidea primates. Rev Esp Antropol Fis.

Here you have the abstract:

Fourier analyses allow extracting parameters from the outline of tooth crowns, which can be used in multivariate analyses. However, the great complexity of some dental shapes forces to check for the intrinsic error produced in this procedure. The main goal of this paper is to apply and validate the Fourier analysis in the study of second lower molar (M₂) crown shape of four Hominoidea species to explore the interspecific morphometric variability, as well as determine the intra- and interobserver error rates. The occlusal surfaces outlines were digitized, derived Fourier functions were calculated, and Discriminant Analyses and Mantel Tests (Pearson correlations) were performed in order to determine the error rates between measurements and interspecific tooth shape variability. Results show that Fourier analyses are able to discriminate variability of molar shapes within Hominoidea primate species. In addition, the high correlation found, both intra- (r>0.9) and inter-observers (r>0.7) suggest that tooth morphometric description by Fourier methods from different observers can be pooled for joint analyses.

Keywords: Hominoidea, tooth, shape, elliptic Fourier analysis.

Resumen

Los análisis de Fourier permiten caracterizar el contorno del diente y obtener una serie de parámetros para un posterior análisis multivariante. Sin embargo, la gran complejidad que presentan algunas formas obliga a determinar el error de medición intrínseco que se produce. El objetivo de este trabajo es aplicar y validar los análisis de Fourier en el estudio de la forma dental del segundo molar inferior (M₂) de cuatro especies de primates Hominoidea para explorar la variabilidad morfométrica interespecífica, así como determinar el error de medición a un nivel intra- e interobservador. El contorno de la superficie oclusal del diente fue definido digitalmente y con las funciones derivadas del análisis de Fourier se realizaron Análisis Discriminantes y Test de Mantel (correlaciones de Pearson) para determinar las diferencias de forma a partir de las mediciones tomadas. Los resultados indican que el análisis de Fourier muestra la variabilidad de forma en dientes molares en especies de primates Hominoidea. Adicionalmente, los altos niveles de correlación a nivel intra- (r>0,9) como inter-observador (r>0,7) sugieren que la descripción morfométrica del diente a partir de métodos de Fourier realizados por diferentes observadores puede ser agrupada para posteriores análisis.

Palabras clave: Hominoidea, diente, forma, análisis elíptico de Fourier.

Morphological characterization of the Hominoidea primates second molars from Fourier analysis

2011-06-04T13:00:00.002+02:00

We recently published a paper, still an on-line accepted manuscript, about tooth morphology characterization in Hominoidea primates by using Fourier analysis, at the Revista Argentina de Antropología Biológica.

Here you have the abstract and a link to the original manuscript

Beatriz Gamarra, Alejandro Romero, Alejandro Pérez-Pérez, Jordi Galbany (2011, accepted) Caracterización morfólogica del M2 de primates Hominoidea a partir de análisis de Fourier/ Morphological characterization of the Hominoidea primates second molars from Fourier analysis. Revista Argentina de Antropología Biológica.

ABSTRACT

Fourier analysis can allow to characterize the shape of teeth, by employing a number of landmarks defining its profile, and extract a number of parameters for subsequent multivariate analysis. However, the great complexity of some cases requires testing how many landmarks are needed for a correct representation. The aim of this paper is to apply and validate the Fourier analysis (Polar and Elliptic) in the dental conformation study by using different contour landmarks, and explore the morphometric variability in different genera. Digital photographs were obtained in occlusal view of second lower molars (M2s) of 4 species of primates (Hylobates moloch, Gorilla beringei graueri, Pongo pygmaeus pygmaeus and Pan troglodytes schweirfurthii). Teeth was defined with 30, 40, 60, 80, 100 and 120 landmarks, and 10 harmonics were obtained in each case. The variability was analyzed by applying Discriminant Analysis and NP-MANOVA from distance matrices to determine the percent of correct classification at methodological and taxonomical levels. The results shown that Fourier analysis detect intergenus variability of shape in M2s of Hominoidea genera, regardless of the number of landmarks defining the contour. The classification rates presented higher variability in Polar (≈60-90) analysis than in Elliptic ones (75-100%). Using between 60-100 landmarks in an elliptic analysis ensures a good discrimination of tooth shapes in Hominoidea.
KEY WORDS: Fourier analysis; molar; primate; Hominoidea.

RESUMEN
Los análisis de Fourier permiten caracterizar el contorno del diente a partir de un número determinado de puntos y extraer una serie de parámetros para un posterior análisis multivariante. No obstante, la gran complejidad que presentan algunas conformaciones obliga a comprobar cuántos puntos son necesarios para una correcta representación de ésta. El objetivo de este trabajo es aplicar y validar los análisis de Fourier (Polar y Elíptico) en el estudio de la forma dental a partir de diferentes puntos de contorno y explorar la variabilidad morfométrica en diferentes géneros. Se obtuvieron fotografías digitales de la superficie oclusal en segundos molares inferiores (M2s) de 4 especies de Primates (Hylobates moloch, Gorilla beringei graueri, Pongo pygmaeus pygmaeus y Pan troglodytes schweirfurthii) y se definió su contorno con 30, 40, 60, 80, 100 y 120 puntos y su representación formal a 10 armónicos. El análisis de la variabilidad morfométrica se analizó mediante la aplicación de Análisis Discriminantes y un NP-MANOVA a partir de matrices de distancias para determinar la variabilidad y porcentajes de clasificación correcta a nivel metodológico y taxonómico. Los resultados indicaron que los análisis de forma con series de Fourier permiten analizar la variabilidad morfométrica de M2s en géneros de Hominoidea, con independencia del número de puntos de contorno (30 a 120). Los porcentajes de clasificación son más variables e inferiores con el uso de la serie Polar (≈60-90) que con la Elíptica (75-100%). Un número entre 60-100 puntos de contorno mediante el método elíptico garantiza una descripción correcta de la forma del diente.
PALABRAS CLAVE: Análisis de Fourier; molar; primate; Hominoidea

SEAF17: Dental ecology in Amboseli baboons

2011-05-30T17:08:00.004+02:00

This week we present some results about dental ecology in Amboseli baboons at the 17^th SEAF Meeting 2011 (“Sociedad Española de Antropología Física”) in Barcelona.

Here you have the presentation.

You can also check our older posts about it, if interested.

SEAF17 Barcelona Meeting

2011-05-26T09:58:00.004+02:00

Next week we celebrate the 17th Spanish Association of Physical Anthropology Meeting, at University of Barcelona. There are some communications on dental ecology in hominids and primates. This meeting also includes a symposium about Neanderthals in Iberia.

Here you have the program schedules and all the abstracts.

X Jornadas de Antropología Biológica

2011-04-08T15:20:00.000+02:00

April 15th and 16th will be the “X Jornadas de Antropología Biológica” at the University of Alicante, organized by Joaquín De Juan, Alejandro Romero, Mª Paz de Miguel, José Luis Girela and Susana Gómez, from de Biotechnology Department. This year the talks are about Neanderthal genomics, Holocene human populations in the Mediterranean, modeling of embryonic development and microevolution, dental ecology in primates and bipedalism and human evolution.
More information is available at the official website, and all talks can be followed online.

Boletín de la Asociación Primatológica Española: Conoce un artículo científico

2011-04-04T17:01:00.005+02:00

It was recently published the last “Boletín de la Asociación Primatológica Española”, where there is a new section “Conoce un artículo científico”. In this occasion they present our paper published by Galbany et al. 2011, about tooth wear and dental ecology in Amboseli baboons, paying attention to the results, the project and fieldwork. You can download it here.
On the other hand, next September will be the III Iberian Primatological Conference, in Almanda (Portugal). There is still time to present the abstracts…

SEAF17 - 2011 Meeting

2011-04-01T08:45:00.002+02:00

In June 2011 (2nd to 4th), we will assist to the 17th Spanish meeting of the “Sociedad Española de Antropología Física”, in Barcelona, and present several communications about primate, human and hominid teeth morphology, dental ecology, dental microwear and taphonomy of teeth. Here you have the abstracts of the presentations.

Enamel taphonomy

Experimental study of acid erosion and abrasion on human dental enamel: characterization of taphonomic alterations in dental microwear pattern.
Andrés Aliaga, Alejandro Romero, Alejandro Pérez-Pérez
Dental microwear studies have been a useful analysis tool to paleobiological interpretations, giving information about dietary and feeding behavior. However, we can observe microscopic alterations related with taphonomic post mortem processes, which are possible distinguish of microwear patterns. We studied the erosive and abrasive effect over buccal microwear patterns of three different acids with different degrees (2.5% hydrochloric acid, pH 0.67; 20% acetic acid, pH 1.82 and citric acid, pH 2.16) and a highly abrasive agent (aluminum oxide particles, Al2O3) at several exposure times by Scanning Electron Microscopy (SEM), both qualitatively such as quantitatively. Main objective was characterize the effect those agents in order to project a parallel with the natural taphonomic activity, for identification of damage of agents that cause post mortem changes. Were analyzed a sample of human post canines teeth, archaeological and freshly extracted. In hydrochloric acid experiment we observed a destructive effect, eliminating any feature. Both acetic and citric acids have displayed a lower destructive effect on enamel surface than hydrochloric acid, thereby following at all times microwear features. Generally, we observe a decrease of microwear density along exposition time. Mean length of total features presented an initial increase on both weak acids, but then was set up a decrease significant with acetic acid. Furthermore, features in Al2O3 experiment was decreased in early exposition stages, but finally there are slight increases. The differences in behavior are not conclusive, due to the size of the sample. We can say which the hydrochloric acids, acetic and citric acids and abrasion with Al2O3 particles cause changes on enamel surface. These changes are proportional to degree of acidity and exposure time. Those results invite us to continue deep studies with in vitro taphonomic agents and perform analysis with larger sample size to obtain more conclusive results.

Primate and hominid dental ecology and dental microwear

El patrón de microestriación dental bucal de A.anamensis revela una ecología alimentaria granívoro-frugívoro similar a la de algunos Cercopithecoidea actuales.
Ferran Estebaranz, Laura M. Martínez, Jordi Galbany, Alejandro Pérez-Pérez
Las reconstrucciones paleoambientales para A. anamensis (4,2-3,9 Ma) indican que habitó en un amplio rango de paleoambientes: bosques abiertos, bosques en galería y sabana arbolada, con una marcada estacionalidad. El patrón de microestriación de A. afarensis, una especie posterior que habitó en la misma zona y en hábitats similares, indica que era una especie frugívora que, durante la estación seca, se alimentaría de fallback foods propios de sabana. Sin embargo, el análisis del patrón de microestriación en los 5 especímenes de A. anamensis con esmalte bucal bien preservado de A. anamensis (de un total de 18) muestra una clara diferenciación entre A. anamensis y A. afarensis. A. anamensis tiene un número de estriaciones total (NT) de 220,60, muy superior a A. afarensis (NT= 150,69) y similar al de los algunos Cercopithecidae (Cercocebus –NT: 210,60; Mandrillus: NT=213,75; Cercopithecus sp.: 244,00). Además, en un ACP (PCI: 30,85%, PCII: 13,27% de la varianza) A. anamensis se distancia claramente de A. afarensis y se agrupa con el resto de primates Cercopithecoidea. Finalmente, en un Análisis Discriminante Descriptivo (FD1: 54,0%, FD2: 19,1%) con una probabilidad posthoc de correcta clasificación del 70,3%, A. anamensis (con un 80% de los especímenes correctamente clasificados) muestra de nuevo claras similitudes con los cercopitecinos. Estos resultados indican que A. anamensis presenta una dieta más abrasiva que la de A. afarensis, con un régimen alimentario de tipo frugívoro-granívoro similar al de algunos Cercopithecidae actuales (semillas, nueces, rizomas, tubérculos, raíces), a diferencia tanto de su predecesor Ardipithecus ramidus, como de A. afarensis.

El patrón de microestriación bucal en Paranthropus robustus y Australopithecus africanus como indicador de cambios ecológicos producidos a lo largo del Plio-pleistoceno
Laura M. Martínez, Ferran Estebaranz, Jordi Galbany, Alejandro Pérez-Pérez
A lo largo del Plio-Pleistoceno y como consecuencia del proceso de formación del Rift Valley, se produjo un fraccionamiento de los ecosistemas y una progresiva tendencia hacia la aridez, lo que conllevaría la desaparición de bosques cerrados y la aparición de extensas sabanas, circunstancias que condicionarían la aparición y desaparición de algunos géneros de homínidos. En el marco de este cambio encontramos en el sur de África dos especies de homínidos diferentes: P. robustus y A. africanus. El gran tamaño mandibular y de la dentición descrito para el género Paranthropus podría representar una estrategia eficaz para el consumo de alimentos que requieren una intensa masticación, como tubérculos, rizomas y raíces. Sin embargo, mientras que los estudios de isótopos sugieren una dieta con abundantes plantas de tipo C4, los estudios del patrón de microestriación en la cara oclusal y bucal de las especies del Este de África parecen no corroborar estos resultados. Por otro lado, la paleoecología asociada a A. africanus corresponde a ecosistemas más cerrados con abundantes recursos que podrían ser explotados de forma intensa a lo largo del año, de forma similar a la estrategia propuesta para A. afarensis en el este de África. Por ello se ha sugerido para esta especie una dieta de tipo generalista y de régimen omnívoro. Ambas especies del sur presentarían por lo tanto estrategias ecológicas distintas que tendrían que reflejarse en su patrón de microestriación. Los resultados de este estudio indican que el patrón de microestriación de P. robustus se asemeja al descrito en las especies de Paranthropus del Este, con un bajo número de estrías que sugiere una dieta poco abrasiva. En cambio, el patrón de A. africanus es similar al de chimpancés y gorilas, con más estrías, similar al descrito para A. afarensis y H. habilis.

Ecologia dental dels papions d’Amboseli
Jordi Galbany, Jeanne Altmann, Laia Dotras, Alejandro Pérez-Pérez, Susan C. Alberts
L’estudi dental en primats vius de poblacions salvatges, com els papions (Papio cynocephalus) d’Amboseli (Kenya), permet valuar el desgast i el microdesgast dental, i alhora determinar la pèrdua de funcionalitat dental. A més, aquest tipus de dades és molt útil per a la construcció de models de l’ús dels recursos tròfics dels homínids Plio-Pleistocènics. El present estudi es va iniciar el 2006, amb la captura de papions d’Amboseli i la presa de motllos dentals. Fins ara, ja s’han pres motllos de més de 150 individus d’ambdós sexes i edats conegudes, pertanyents a cinc grups socials diferents de la mateixa població. A partir dels motllos s’han obtingut dades del desgast dental i microdesgast dental, entre altres variables. Els resultats mostren una clara transformació macroscòpica de les dents associada a l’envelliment. Concretament, es va calcular el percentatge d’exposició de dentina i el relleu de les corones dentals com a indicadors del desgast oclusal. Aquestes dues variables presenten una elevada correlació significativa amb l’edat, tant per mascles com per femelles. Però, al mateix temps, també correlacionen significativament amb el percentatge de consum d’aliments molt abrasius que presentaven els diferents individus. A més, els segons premolar (P4) i els primers molars (M1) presenten un evident desgast interproximal i correlacionat significativament amb l’edat. La transformació morfològica de les dents d’aquests primats està clarament associada a processos d’envelliment, entre d’altres causes ecològiques i sociobiològiques. Els futurs estudis de variables biològiques, tals com l’èxit reproductor, el rang social o la supervivència dels individus, permetrà determinar si aquest envelliment implica una pèrdua de funcionalitat i de fitness a la població.

División de tareas en el paleolítico y su impacto en la dieta
Beatriz Pinilla, Alejandro Pérez-Pérez
La microestriación bucal permite establecer comportamientos alimentarios y por lo tanto puede arrojar luz a la hora de comprobar si el grado de diferencias en los patrones dietarios de los AMH en Europa es similar al de los cazadores-recolectores recientes, como se ha propuesto recientemente (Kuhn & Stiner, 2006; 2009) y establecer si había y cuáles eran las diferencias entre individuos de diferente sexo. La muestra estudiada incluye moldes dentales de 96 cazadores-recolectores actuales (un diente por individuo) y 378 AMH (78 individuos). La muestra se ha segmentado por sexos obteniendo microestriación de 9 individuos femeninos y 11 masculinos del Paleolítico Superior. Los resultados obtenidos indican que no existen diferencias significativas entre los sexos en ninguno de los grupos estudiados; consecuencia seguramente del aumento de la socialización. Los AMH presentan unas diferencias en la dieta entre los sexos, similares a las de los cazadores-recolectores actuales. El aumento de la independencia económica de las mujeres, debería implicar una dieta más abrasiva en las hembras. Los datos muestran sin embargo un patrón variable, relativamente mediado por el clima, posiblemente relacionado con requerimientos energéticos.

Human and primate teeth morphology
Morfometría dentaria en grupos neolíticos de Kenia (Este de África)
Maite Artero, Alejandro Romero, Jordi Galbany, Beatriz Gamarra, Beatriz Pinilla, Alejandro Pérez-Pérez
El fenotipo cráneo-mandibular y su plasticidad se relacionan con adaptaciones ecológicas y alimentarias. Existen evidencias de una reducción de la dentición postcanina durante el Neolítico asociada a nuevos sistemas de subsistencia. No obstante, la variabilidad morfométrica del diente entre poblaciones con cronología diferente y similar tipo de dieta es poco conocida. Si el factor alimentario condiciona la forma y tamaño del diente, la distancia cronológica no debería afectar su estructura. Para explorar esta hipótesis, se aplicaron métodos de Morfometría Geométrica 2D en una muestra de segundos molares (M2) de grupos pastores neolíticos (≈2000 BP) y modernos (Kikuyu, Maasai y Miaou) localizados en el centro y sur del Valle del Rift en Kenia (Este de África). Combinando landmarks y semilandmarks para describir el área oclusal de la corona, se registró el tamaño y la forma del diente y se calculó la alometría intra e intergrupo a través del análisis multivariante de ambas variables. Los resultados muestran diferencias significativas en la morfometría entre grupos cronológicos (λ = 0,104, χ2 = 49,889, p=0,01) y rechazan la hipótesis planteada. Las diferencias se definen principalmente por un mayor metacono en el grupo neolítico, así como una mayor distancia entre el paracono y metacono en los modernos, que no afecta a las diferencias en el tamaño del diente (Centroid Size – CS) entre grupos (p>0,05). Se observa una reducción dentaria no significativa en los grupos modernos (CS = 30,636) con respecto a los neolíticos (CS = 32,069) y regresión alométrica no significativa (F de Goodall, p>0,05) lo que demuestra un escalamiento isométrico del diente entre grupos. La ecología, la dieta y las relaciones ancestro-descendiente son los factores evaluados como causa de la variación observada.

Morfología dentaria en cazadores-recolectores pigmeos de África Central
Alejandro Romero, Fernando V. Ramírez-Rozzi, Joaquín De Juan, Alejandro Pérez-Pérez
Los pigmeos son grupos cazadores-recolectores que habitan selvas tropicales de África ecuatorial y conviven con poblaciones bantúes agrícolas. Estos grupos presentan un flujo genético asimétrico y una divergencia de un ancestro común. Estudios previos establecen claras diferencias en la forma del cráneo entre ellos y una alometría negativa entre el tamaño del diente y cráneo en pigmeos. Sin embargo, la relación del tamaño y proporciones de las cúspides del diente desde una perspectiva alométrica no se había analizado hasta ahora. En este estudio se midió y cuantificó en mm2 el área de la corona (TCBA) y de las cúspides del primer molar maxilar, a partir de imágenes digitales en una muestra de pigmeos y bantúes no-pigmeos de África Central. La muestra se agrupó en pigmeos del oeste (n = 28 WPpigmeos del este (n = 7 EP), y no-pigmeos del oeste (n = 37 WNP) y este (n = 36 ENP). Los resultados indican que TCBA es significativamente mayor (ANOVA p<0,05) en pigmeos y confirma una alometría negativa en el tamaño del diente en relación al cráneo. Sin embargo, esta diferencia es sólo significativa (post-hoc HSD de Tukey p<0,01) entre WP y WNP. El mayor tamaño del diente en pigmeos se debe a un mayor tamaño del protocono e hipocono. El análisis de covarianza revela una homogeneidad en la pendiente (p>0,05) y no indica diferencias en la forma del diente entre pigmeos y no-pigmeos. A nivel intragrupo la mayoría de las cúspides presentan una isometría con respecto a TCBA, únicamente la pendiente de regresión es significativa (p<0,01) para el paracono en WP presentando una alometría negativa. Nuestros resultados, basados en proporciones intercuspidales (distancia euclídea), explican un modelo de ramificación similar al obtenido a partir del análisis de ADN en pigmeos y poblaciones bantúes.

Análisis de Fourier en molares de primates: evaluación metodológica y variabilidad morfológica dental
Beatriz Gamarra, Alejandro Romero, Maite Artero, Alejandro Pérez-Pérez, Jordi Galbany
El análisis de la forma y tamaño del diente en Primates no-humanos, y su variabilidad interespecífica, ha demostrado su importancia en estudios filogenéticos y adaptativos. Estudios previos, validan el análisis de contorno de las coronas dentales con series de Fourier como método para explorar diferencias en la morfología dental y clasificación filogenética en especies de mamíferos. Sin embargo, esta metodología no se ha aplicado en Primates. El presente trabajo ha empleado una muestra de segundos molares inferiores (M2) de Primates Hominoidea para indagar en el error de medición (EM) intra e interobservador y en el número óptimo de puntos que definen el contorno dental. En primer lugar, fue necesaria la estandarización y caracterización de la metodología a seguir para este grupo. A partir de una muestra de molares de Hominoidea, los resultados obtenidos demuestran que la metodología que mejor discrimina y que optimiza los resultados es el análisis elíptico de Fourier (EFA), en contraposición al análisis de Fourier con series polares, y un contorno definido con un número superior de 80 puntos (>80% de clasificación correcta), siendo 100 el que mejores resultados obtiene. Adicionalmente, en un análisis conjunto de molares de Hominoidea y Cercopithecoidea empleando esta metodología, los resultados demuestran que la técnica de análisis morfológico discrimina las especies analizadas y explica una clara variabilidad siguiendo criterios filogenéticos.

Variabilidad morfométrica dental de los primates Simiiformes
Mónica Nova Delgado, Beatriz Gamarra, Alejandro Romero, Alejandro Pérez-Pérez, Jordi Galbany
El presente estudio plantea un análisis de la forma de los molares (M2 inferior) de primates Simiiformes, para determinar sus posibles relaciones filogenéticas y adaptativas, mediante el método de morfometría geométrica. La técnica de thin-plate spline (TPS) permite la visualización de las deformaciones ocurridas en un espacio bidimensional, sobre un conjunto de puntos de referencia (landmarks) en relación a una configuración consenso, además de una interpretación y evaluación de estas diferencias, mediante un análisis multivariado. Se analizó una muestra de 116 especímenes de distintos grupos taxonómicos de primates (Hominoidea, Cercopithecoidea y Ceboidea). La forma de los dientes fue definida a partir del registro de 12 landmarks de tipo 2 (4 cúspides, 4 curvaturas máximas de la corona y 2 intersecciones de los surcos vestibulares y lingual de la corona) y tipo 3 (2 puntos de contacto medio interdental en ambos lados). Los partial warps y el componente uniforme derivados del análisis morfométrico, fueron utilizados para el Análisis Discriminante. Los resultados mostraron que las especies de Hominoidea y Cercopithecoidea se encuentran distribuidas de forma opuesta para la F1 en el morfoespacio. Los Ceboidea se solaparon ligeramente con los Hominoidea, con excepción del género Alouatta. Finalmente, se obtuvieron dendrogramas a partir de los centroides de cada grupo, con el fin de comparar la variabilidad de la forma dental y las relaciones filogenéticas de los primates empleados para el estudio. Los resultados indican que existe un paralelismo entre los datos arrojados de la clasificación taxonómica tradicional de los primates y la forma de los molares, sugiriendo que la forma dental presenta un fuerte componente filogenético.

Geometric Morphometrics analysis of the anterior teeth of Paleolithic European populations
Katarzyna Górka, Beatriz Pinilla, Alejandro Pérez-Pérez
Following article presents the results of a research, which main objective was to determine whether, and if so, under which factors, the shape of anterior teeth changes, among three Paleolithic Homo populations. The research was based on a sample of 180 anterior teeth (incisors and canines) of H.heidelbergensis, H.neanderthalensis and H.sapiens populations from Paleolithic period. Four hypotheses were established: 1) the shape of the anterior teeth varies among populations of the Homo genus; 2) the shape of the anterior teeth varies among MIS climatic periods but not among populations; 3) the shape of the anterior teeth varies among populations from different geographic regions; and 4) high level of a tooth wear causes changes in the shape of the teeth. Geometric morphometrics was used to detect the changes in the shape of the teeth, with 5 landmarks and 30 semi-landmarks selected. Discriminant function analysis for four independent factors (population, geography, MIS and wear stage) was performed. The results indicate differences in the shape of anterior teeth among Paleolithic Homo populations. Also geographic dispersion, Marine Isotope Stage chronology and progressive tooth wear were significantly discriminated by the differences in the shape of the anterior teeth. The analysis served as a preliminary study of anterior teeth as this kind of research, on this material, was not performed yet. The results may serve as a base for further and deeper analysis of the influence on the shape of the teeth of each of the analyzed factors separately and therefore can be used to interfere about ecological adaptations, diet and relations between analyzed populations. Also further research may answer the question whether Natural Selection favours any specific kind of tooth morphology depending on the environment or dietary adaptations.

East African australopithecine buccal dental microwear reveals that A. anamensis’ feeding ecology was Cercopithecoidea-like

2011-03-16T15:02:00.001+01:00

From August 8th to 12th, 2011, Ferran Estebaranz will present a talk at the 3rd East African Association for Palaeoanthropology and Palaeontology (EAAPP) Conference in Addis Ababa, Ethiopia. Here you have the abstract.

East African australopithecine buccal dental microwear reveals that A. anamensis’ feeding ecology was Cercopithecoidea-like.
Estebaranz, F, Martínez, L.M., Galbany, J., Pérez-Pérez, A.

Secció Antropologia, Departament de Biologia Animal, Facultat de Biologia, UNiversitat de Barcelona. Av. Diagonal 645, 08028 Barcelona. martinez.perez-perez@ub.edu

Paleoenvironmental reconstructions of A. anamensis (4.2 to 3.9 Ma) indicate that it inhabited a wide range of habitats, from open or gallery forests to savanna woodlands with a marked seasonality. Both buccal and occlusal microwear patterns of A. afarensis (a more recent species that inhabited the same region and similar habitats) dental enamel surfaces (Grine et al., 2006; Estebaranz et al., 2009) have indicated that it was a frugivorous species that consumed fallback foods and savanna resources during the dry season. However, the buccal microwear patterns of dental enamel surfaces of 5 well-preserved fossil specimens of A. anamensis (out of 18 studied) showed a distinct striation density for A. anamensis (NT=220.6) that clearly differed from that of A. afarensis (NT=150.7) and more closely resembled those of the papionini (Cercocebus NT=210.6; Mandrillus NT=213.8; Cercopithecus NT=244.0). Furthermore, within a PCA (Principal Component Analysis) A. anamensis differed from A. afarensis and clearly clustered with the Cercopithecoidea primates studied. Finally, a LDA (Linear Discriminant Analysis) of all groups studied again showed greater similarities of A. anamensis with the cercopithecins than with A. afarensis. These results, that contrast with previous occlusal microwear interpretations (Grine et al., 2006; Ungar et al., 2010), suggest that A. anamensis most likely had a granivorous-frugivorous diet, much more abrasive than that of A. afarensis and similar to those of the extant papionini, mainly based on seeds, nuts, rhizomes, tubers and roots.

Molar crown size in African Pygmy hunter-gatherers and Bantu-speaking farmers

2011-02-27T18:10:00.001+01:00

In April 2011 we are presenting a poster about tooth size in African populations at the AAPA meeting. Here you have the abstract.

Molar crown size in African Pygmy hunter-gatherers and Bantu-speaking farmers

ALEJANDRO ROMERO1, FERNADO V. RAMIREZ ROZZI2, ROBERTO DE LA TORRE1, ALAIN FROMENT3, JOAQUÍN DE JUAN1, ALEJANDRO PÉREZ-PÉREZ4. 1Department of Biotechnology, University of Alicante (Spain), 2UPR 2147 CNRS, Dynamique de l’évolution humaine, Paris (France), 3IRD UMR 208, Musée de l’Homme, Paris (France), 4Department of Animal Biology, University of Barcelona (Spain).

African pygmies and Bantu farmers living in close relationship differ quite clear in genetic and in morphology. Previous works based on linear dimensions have shown that teeth are enlarged in dwarfed populations in relation to skull dimensions, but no differences were found in absolute dimensions neither in tooth scaling between pygmies and non-pygmies. Nevertheless, few studies have looked at specific morphological traits of the Pygmy’s dentition. The crown base area (CBA) and cusp units (trigon-TR and hypocone or talon-TL) of the upper M1 were analyzed in a sample of Western pygmies (WPYG) (Baka, BaBinga and BaBongo, n=28), Eastern pygmies (EPYG) (Mbuti and Efe, n=7) and Bantu speakers (Bateke-Balali, Pahouin and Yakoma, n=30) inhabiting the rainforest of equatorial Africa. Univariate (ANOVA and post-hoc Tukey’s HSD test) (p<0.05) and Canonical Discriminant Functions analyses, were used to plot differences between groups. Results indicate that CBA, TR and TL are significant larger in Pygmies (W & E) than in Bantu, these differences can explain in themselves a negative allometry in tooth size related to cranial dimension in dwarfed populations. When WPYG and EPYG are considered separately, only WPYG show differences with Bantu in CBA and TL. Analysis of tooth scaling reveal strong allometric pattern in each group. Finally, the Discriminant Analysis shows greater variability among Pygmies due to important changes in the trigon. Our results, based on tooth morphology, show similar results to those based on DNA analyses.

This study was funded by Spanish GV and MEC, grant numbers BEST/2009/258, CGL2007-60802 and Wenner-Gren Foundation, grant number Gr.7819.

Interproximal tooth wear in Amboseli baboons

2011-02-13T18:15:00.005+01:00

A new paper about dental ecology in Amboseli baboons just came out at Folia Primatologica. You can download it in the journal website or ask us for a copy.

Jordi Galbany, Laia Dotras, Susan C. Alberts & Alejandro Pérez-Pérez (2010) Tooth size variation related to age in Amboseli baboons. Folia Primatologica 81(6):348-359.

Abstract
We measured the molar size from a single population of wild baboons from Amboseli (Kenya), both females (n = 57) and males (n = 50). All the females were of known age; the males represented a mix of known-age individuals (n = 31) and individuals with ages estimated to within 2 years (n = 19). The results showed a significant reduction in the mesiodistal length of teeth in both sexes as a function of age. Overall patterns of age-related change in tooth size did not change whether we included or excluded the individuals of estimated age, but patterns of statistical significance changed as a result of changed sample sizes. Our results demonstrate that tooth length is directly related to age due to interproximal wearing caused by M2 and M3 compression loads. Dental studies in primates, including both fossil and extant species, are mostly based on specimens obtained from osteological collections of varying origins, for which the age at death of each individual in the sample is not known. Researchers should take into account the phenomenon of interproximal attrition leading to reduced tooth size when measuring tooth length for ondontometric purposes.

Key Words
Molar size, Interproximal wearing, Aging, Papio cynocephalus, Amboseli, Kenya

Baboon tooth molding

P4 and molar occlusal surfaces of Amboseli baboons representing different
ages. Older individuals present higher occlusal and interproximal tooth wear

Dental microwear in Bantu and Baka populations

2011-01-30T18:26:00.005+01:00

Fernando Ramírez-Rozzi and Alejandro Romero are analyzing dental microwear patterns of Bantu and Baka African populations from Cameroon. First results were presented at the last AAPA meeting. Here you can watch a video where Dr. Ramírez-Rozzi explains the project and shows how the dental molds are obtained and analyzed.

http://www.youtube.com/watch?v=sB34kzfgYEk

Photographic and descriptive musculoskeletal Atlas of Gorilla

2011-01-09T11:15:00.008+01:00

A couple of researchers in our group, Gaëlle Bello and Josep M. Potau, are authors of this new book. Is not about primate dental ecology, but interesting to talk about it in our blog.

Book cover

Here you have the summary:

Even though the gorilla is one of our closest living relatives, information about its anatomy, and particularly its musculature, is scarce. This book is the first photographic and descriptive musculoskeletal atlas of the gorilla. It includes high-quality photographs of musculoskeletal structures from most anatomical regions of the body, along with textual information about the attachments, innervations, and weight of the reported muscles. The atlas is an up-to-date review of the anatomical variations within gorillas as well as an extensive list of the synonyms used in the literature to designate the structures covered in the book. It also contains dissection observations of other primates and vertebrates, which are crucial for examining and understanding the homologies between the muscular structures of gorillas, humans, and other taxa.

Click here if you’re interested in acquiring it.

Origin and evolution of teeth: from the primitive chordates to modern humans

2010-12-09T13:24:00.004+01:00

New paper about tooth morphology in primates and hominids…

Pérez-Pérez A, Galbany J, Romero A+, Martínez LM, Estebaranz F, Pinilla B & Gamarra B (2010) Origen y evolución de los dientes: de los cordados primitivos a los humanos modernos. Revista Española de Antropología Física 31: 167-192.
Secc. Antropología. Dpto. Biología Animal. Universitat de Barcelona. Av. Diagonal 645, 08028 Barcelona.
+ Dpto. Biotecnología, Facultad de Ciencias. Universidad de Alicante.

Origin and evolution of teeth: from the primitive chordates to modern humans
Abstract
The teeth of vertebrates, especially mammals, show a great diversity of forms as a result of ecological and dietary adaptations in relation to habitat preferences and ecological conditions. The dental anatomy is useful to define and characterize populations and species, and has been used extensively to define new taxa, and phylogenetic relationships among groups. Our research on the morphological evolution of the hominin dentition has highlighted the importance of the teeth in the characterization of the diet and the ecological adaptations of our ancestors. This study is the first in a series of three papers in which we consider the importance of the dental anatomical features in the interpretation of the evolution of our lineage. It describes the major evolutionary events that gave rise to the teeth and their diversification. In subsequent works we will analyze in greater detail the diversification of the teeth of mammals and primates.
Key words: teeth, anatomy, evolution, mammals, primates, hominins

Origen y evolución de los dientes: de los cordados primitivos a los humanos modernos
Resumen
Los dientes de los vertebrados, y especialmente de los mamíferos, muestran una gran diversidad de formas como resultado de las adaptaciones ecológicas y alimentarias de las especies en función del hábitat y las condiciones ecológicas. La anatomía dental es de gran utilidad para definir especies y caracterizar poblaciones, y se ha utilizado extensamente para definir nuevos taxones y establecer relaciones filogenéticas. Nuestras investigaciones sobre la evolución morfológica de la dentición de los homininos han puesto de relieve la importancia de los dientes en la caracterización de las adaptaciones ecológicas de nuestros antepasados. El presente trabajo es el primero de una serie de tres trabajos que nos planteamos sobre la importancia de las características anatómicas en la interpretación de la evolución de nuestro linaje. En él se describen los principales eventos evolutivos que dieron origen a los dientes y su diversificación.
Palabras clave: dientes, anatomía, evolución, mamíferos, primates, homininos

We can send it to you upon request...

Bilophodont (Colobus sp.) and bunodont (Pan troglodytes) molar teeth

A new dissertation on dental microwear: Plio-Pleistocene hominids

2010-12-01T15:59:00.007+01:00

On December 20th, Laura M. Martínez will present her Dissertation titled “Variability of dental microwear pattern in Plio-Pleistocene hominids from eastern and southern Africa” at the University of Barcelona, directed by Dr. Alejandro Pérez-Pérez (6 pm - Aula Magna, Facultat de Biologia, Universitat de Barcelona).

This work has analyzed the buccal dental microwear pattern in several hominid species (Australopithecus anamensis, A.afarensis, A.africanus, Paranthropus aethiopicus, P.boisei, P.robustus, Homo habilis and H.ergaster) from different sites (Hadar, Turkana, Olduvai, Peninj, Sterkfontein, Swartkrans, Makapansgat, Kromdraai, Gladysvale), to trace dietary specializations. The results for 114 fossils, compared to Hominoidea and Ceropithecoidea primates, clearly show differences between the hominids and support that dietary specialization might have been a means to avoid ecological competition between hominids during the Plio-Pleistocene climatic shift in Africa.

Some of the final results presented here were previously published.

Estebaranz F, Martínez LM, Galbany J, Turbón D & Pérez-Pérez A (2009) Testing hypotheses of dietary reconstruction from buccal dental microwear in Australopithecus afarensis. Journal of Human Evolution 57: 739-750.

Galbany J, Estebaranz F, Martínez LM & Pérez-Pérez A (2009) Buccal dental microwear variability in extant African Hominoidea primates: taxonomy versus ecology. Primates 50(3): 221-230.

Olduvai Gorge monolith

Age related variability of buccal dental microwear patterns in hominids from Europe

2010-09-04T19:11:00.002+02:00

We recently presented some results on dental microwear in Neanderthals and humans at the 17^th Congress of the European Anthropological Association, in Poznań (Poland). Here you have the abstract…

Age related variability of buccal dental microwear patterns in H. heidelbergensis, H. neanderthalensis and H. sapiens fossil specimens from Europe

Beatriz Pinilla & Alejandro Pérez-Pérez

Secc. Antropologia, Dept. Biologia Animal. Fac. Biologia, Universitat de Barcelona. Av. Diagonal 645, 08028 Barcelona (Spain).

We have analyzed a sample of 803 teeth corresponding to anatomically modern humans (AMH), Neanderthals and H. heidelbergensis fossil specimens from various European sites. From these, 263 showed well-preserved buccal dental microwear patterns, defined from the density, length and standard deviation of the length of all scratches present in a 0.56 mm2 buccal enamel patch, considering four orientation categories. The infant and juvenile individuals showed low striation densities, with increasing roughness with age. Buccal dental microwear has been shown to stabilize 10 years after tooth eruption, thus constituting a reliable indicator of overall dietary habits of adult individuals. We have analyzed the variability of the buccal microwear pattern in relation to dental age. The AMH infants showed a microwear pattern similar to the adults’ one, only differing in the density of MD striations. The Neandertals and H. heidelbergensis children had distinct microwear patterns compared to their elders: the young Neanderthals showed significant differences in striation density (NH, NDM, NT) and length (XH, XV, XDM, XT); and H. heidelbergensis children differed from the adults in striation density (NV, NT) and length (XH, XV, XT). The shift in microwear patterns from infants to adults in the AMH sample was mainly caused by an increase in striation density, wheareas in the Neandertal and H. heidelbergensis samples the change was more significant in striation lenghts, which were larger than in the adults. Despite the fossil sample was small, its analysis by dental eruption ages showed no clear cumulative pattern of striation densities. The differences in microwear patterns observed among infants of the studied species (H. heidelbergensis, H. neanderthalensis, H. sapiens) suggest that differences in food exploitation techniques and diet affected the young individuals in a different manner than the adults, being in both cases informative of dietary adaptations and food processing strategies.

Keywords: teeth, microwear, fossil, Neandertal, human

Mounted Neanderthal replica at AMNH

The life history context of reproductive aging in a wild primate model

2010-09-01T14:04:00.004+02:00

Last week was published a new paper about Amboseli baboons aging, including tooth wear…

Altmann J, Gesquiere L, Galbany J, Onyango PO, Alberts SC (2010) The life history context of reproductive aging in a wild primate model. Annals of the New York Academy of Sciences 1204: 127-138.

Here you can download it.

Abstract
The pace of reproductive aging has been of considerable interest, especially in regard to the long postreproductive period in modern women. Here we use data for both sexes from a 37-year longitudinal study of a wild baboon population to place reproductive aging within a life history context for this species, a primate relative of humans that evolved in the same savannah habitat as humans did. We examine the patterns and pace of reproductive aging, including birth rates and reproductive hormones for both sexes, and compare reproductive aging to agerelated changes in several other traits. Reproductive senescence occurs later in baboon females than males. Delayed senescence in females relative to males is also found in several other traits, such as dominance status and body condition, but not in molar wear or glucocorticoid profiles. Survival, health, and well-being are the product of risk factors in morphological, physiological, and behavioral traits that differ in rate of senescence and in dependence on social or ecological conditions; some will be very sensitive to differences in circumstances and others less so.

Keywords: reproductive aging; baboons; toothwear; body condition; steroid hormones; senescence

Age and individual foraging behavior predict tooth wear in Amboseli baboons

2010-08-21T20:13:00.008+02:00

August 18th was published on-line a paper about tooth wear, age and feeding behavior in Amboseli baboons. You can download it here or ask us for a copy.

Jordi Galbany, Jeanne Altmann, Alejandro Pérez-Pérez & Susan C. Alberts (2011) Age and individual foraging behavior predict tooth wear in Amboseli baboons. Am J Phys Anthropol 144(1): 51-59.

Abstract
Teeth represent an essential component of the foraging apparatus for any mammal, and tooth wear can have significant implications for survival and reproduction. This study focuses on tooth wear in wild baboons in Amboseli, southern Kenya. We obtained mandibular and maxillary tooth impressions from 95 baboons and analyzed digital images of replicas made from these impressions. We measured tooth wear as the percent dentine exposure (PDE, the percent of the occlusal surface on which dentine was exposed), and we examined the relationship of PDE to age, behavior, and life history variables. We found that PDE increased significantly with age for both sexes in all three molar types. In females, we also tested the hypotheses that long-term patterns of feeding behavior, social dominance rank, and one measure of maternal investment (the cumulative number of months that a female had dependent infants during her lifetime) would predict tooth wear when we controlled for age. The hypothesis that feeding behavior predicted tooth wear was supported. The percent of feeding time spent consuming grass corms predicted PDE when controlling for age. However, PDE was not associated with social dominance rank or maternal investment.

Keywords: aging, feeding behavior, foraging, Papio cynocephalus

Tooth wear in function of age in Amboseli baboons

Female baboon feeding on grasses

Teeth molding in Amboseli

Australopithecus afarensis dental microwear

2010-08-13T20:04:00.006+02:00

Posted on Wednesday, October 28 in www.microwear.eu

A new paper about buccal dental microwear in hominids has been published in Journal of Human Evolution.

Testing hypotheses of dietary reconstruction from buccal dental microwear in Australopithecus afarensis

F. Estebaranz, L.M. Martínez, J. Galbany, D. Turbón, A. Pérez-Pérez

A recent study of occlusal microwear in Australopithecus afarensis described this species as an opportunistic dweller, living in both forested and open environments and greatly relying on fallback resources and using fewer food-processing activities than previously suggested. In the present study, analysis of buccal microwear variability in a sample of A. afarensis specimens (n=75 teeth) showed no significant correlations with the ecological shift that took place around 3.5 Ma in Africa. These results are consistent with the occlusal microwear data available. In fact, significant correlations between buccal and occlusal microwear variables were found. However, comparison of the buccal microwear patterns showed clear similarities between A. afarensis and those hominoid species living in somewhat open environments, especially the Cameroon gorillas. A diet based mainly on succulent fruits and seasonal fallback resources would be consistent with the buccal microwear patterns observed.

Keywords: Buccal dental microwear, Diet, Australopithecus afarensis, Ecology

Australopithecus afarensis reconstruction from the AMNH, New York

Scanning Electron Microscope image of buccal dental microwear obtained from an A.afarensis

Dissertation about Mesolithic-Neolithic transition based on dental microwear

2010-08-13T20:00:00.002+02:00

Posted on Thursday, November 5, 2009 in www.microwear.eu

On November 12th, Mohammad Alrousan presented his Dissertation titled “The Mesolithic-Neolithic Transition in the Near East: Biological implications of the shift in subsistence strategies through the analysis of dental morphology and dietary habits of human populations in the Mediterranean area 12,000-5,000 B.P”, under the direction of Dr. Alejandro Pérez-Pérez. This work has analyzed the Mesolithic/Neolithic transition in the Mediterranean basin -an important event in the history of the humankind- by analyzing buccal dental microwear, to determine dietary changes in several populations from Iberian Peninsula and Near East.

Alrousan’s Ph.D. concludes that this transition, in the Near East, caused a limited change in the dietary texture, and Natufian populations had a highly abrasive diet that did not greatly differ from that of the pre-pottery Neolithic populations from the same area, both including domesticated plants and retaining hunter-gathered adaptations as a complementary food resources. On the other hand, the Mesolithic/Neolithic transition in the Iberian Peninsula was more prominent and faster. A dramatic shift in the subsistence economy took place from a fishing and gathering to an agricultural economy, a change clearly evident in the buccal microwear pattern. Moreover, this work also provides information about tooth size and tooth wear in the same populations.

Dental microwear and interproximal tooth wear in Albuquerque AAPA meeting 2010

2010-08-13T19:51:00.008+02:00

Posted on Monday, January 4, 2010 in www.microwear.eu

In April 2010 we are presenting two new posters about dental microwear and interproximal tooth wear, in the AAPA meeting - Albuquerque, NM. Here you have the abstracts and the posters.

Buccal dental-microwear analysis among Pygmy hunter-gatherers from Western Central Africa
Alejandro Romero1, Fernado V. Ramírez-Rozzi2, Alain Froment3, Joaquín De Juan1, Alejandro Pérez-Pérez4

1Department of Biotechnology, University of Alicante (Spain), 2CNRS, Dynamique de l’évolution humaine, Paris (France), 3Musée de l’Homme, Paris (France), 4Department of Animal Biology, University of Barcelona (Spain).

Buccal-tooth surface microwear is highly correlated with abrasive particles in foodstuffs during chewing. However, human microwear-dietary models related to ecological and cultural factors are still scarce. African pygmies are foragers’ societies living in the tropical forest. The analysis of enamel microwear in these populations should provide a good model for societies living in similar environmental conditions. Replicas of left-lower M1 were obtained in a sample of in vivo Baka pygmies from southeastern Cameroon (n=42), BaBinga (n=5) and BaBongo (n=6) museum pygmies from Central African, Congo and Gabon, and a control group of Spanish volunteers (n=36). Buccal-microwear was examined with a Scanning Electron Microscope (SEM) at 100×. Microstriation density and length by orientation (in 45° intervals) from 0° to 180° were measured. Significant differences (ANOVA and Tukey’s HSD tests; p<0.05)>
This study was funded by Spanish GV and MEC, grant numbers BEST/2009/258, CGL2007-60802 and Wenner-Gren Foundation, grant number Gr.7819.

Molar size variation related to age in Amboseli baboons (Papio cynocephalus)
Jordi Galbany1, Laia Dotras2, Jeanne Altmann3, Alejandro Pérez-Pérez2, Susan C. Alberts1.

1Department of Biology, Duke University, 2Department of Animal Biology, University of Barcelona (Spain), 3Department of Ecology and Evolutionary Biology, Princeton University.

Tooth size is a common variable used in primatological and anthropological studies. It can provide information about tooth development, phylogeny or ecological adaptation. Moreover, several studies have evaluated sexual dimorphism by using dental size in primates; dimorphism is particularly remarkable in the canines. But some researchers have pointed out that tooth size can be modified by the degree of interproximal tooth wear, i.e., wear between the teeth that generates attrition and wears away the rounded profile of the crown. Interproximal tooth wear is known to increase with age in humans, but has not been investigated before in natural populations of non-human primates. In the present study, we examined molar size from a single well-known aged population of wild baboons from Amboseli (Kenya), both males (n=41; from 7.4 to 20.45 years old) and females (n=54; from 5.53 to 26.64 years old). The results showed a significant reduction in the mesiodistal length of lower M1 in males and females, as a function of age. There was also a reduction in upper M1 length as a function of age, significant in females, and also a non-significant trend in reduction of length in the M2 for both sexes. These results demonstrate that molar size, especially M1, is directly related to age due to interproximal wearing caused by M2 and M3 compression loads. Researchers should take into account this phenomenon when measuring tooth length for ondontometric purposes.
This research was funded by the US National Science Foundation (BCS-0323553 and BCS-0323596) and the Spanish CGL2004-00775/BTE and CGL2007-60802 projects.